Study Evaluates Strawberry Resistance to Powdery Mildew

WIMAUMA, FL--Powdery mildew is a major threat to strawberries that has been found everywhere strawberries are grown. The invasive fungal disease thrives in open field and high tunnel production environments. When powdery mildew infects strawberry plants, plant vigor is reduced and fruit may become malformed or aborted. Looking for ways to reduce the incidence of powdery mildew, breeders have turned to strawberry's wild "relatives" as a source of beneficial traits. Scientists from the Gulf Coast Research and Education Center at the University of Florida screened an elite group of wild strawberry accessions and important cultivars for resistance to powdery mildew under field and high tunnel production systems. The results of the new research can be beneficial for strawberry breeders interested in minimizing the disease.

Production systems such as high tunnels and rowcovers provide alternative means of protecting Florida strawberries from freeze damage. Although the systems are becoming more popular for season extension and frost protection throughout the world, the lack of free water in the production systems create conditions favorable for development of powdery mildew. The impact of powdery mildew on strawberry crops can mean substantial crop loss and reduced profits for strawberry growers.

Researchers Colleen Kennedy, Tomas Hasing, Natalia Peres, and Vance Whitaker screened an elite group of wild strawberry accessions for resistance to powdery mildew under open-field and high tunnel production systems during the 2010–2011 and 2012–2013 growing seasons. "Our analysis revealed significant differences among genotypes for resistance to powdery mildew as evidenced by a highly significant effect of genotype in the model," they noted, adding that there were also "significant differences" among taxon groups.

"Many breeders have turned to wild relatives (of commercial strawberry) as a source of beneficial traits," said Vance Whitaker, corresponding author of the study published in the HortScience. "There are sources of powdery mildew resistance among elite accessions of the available wild germplasm that have exhibited greater resistance than commercial cultivars. However, many wild accessions appear to be much more susceptible than current cultivars and should be used with caution." The researchers cautioned that if breeders decide to use the most susceptible wild genotypes to access other important traits, there may be a risk of introducing powdery mildew susceptibility into the breeding population.

###

The complete study and abstract are available on the ASHS HortScience electronic journal web site: http://hortsci.ashspublications.org/content/48/9/1125.abstractFounded in 1903, the American Society for Horticultural Science (ASHS) is the largest organization dedicated to advancing all facets of horticultural research, education, and application. More information at ashs.orgOriginal Article:Evaluation of Strawberry Species and Cultivars for Powdery Mildew Resistance in Open-field and High Tunnel Production SystemsColleen Kennedy, Tomas N. Hasing, Natalia A. Peres, and Vance M. WhitakerHortScience 48:1125-1129. [Abstract]Corresponding author. E-mail: vwhitaker@ufl.edu